Spring clutch mechanisms are well known in the art such as disclosed in, for example, U.S. Pat. No. 3,128,863 which issued Apr. 14, 1964 To D. R. Tomko and U.S. Pat. No. 3,528,533 which issued Sept. 14, 1970 to C. R. Sacchini. The spring clutch mechanism disclosed in these patents have input drums which are rotatively driven in a selected direction and include a cross-over gap or slot between the drums for control of chatter. The cross-over gap is provided so that the over-running torque exerted on the spring coils next to the cross-over will be less than that required to cause the coil porton to contact and grip the cross-over surface. In both of these spring clutch mechanisms the input drum is continuously rotated in one selected direction, as aforementioned, and, when the spring clutch is in an engaged operative condition, the output drum is continuously rotated in that selected direction. The present invention is directed to a spring clutch mechanism, wherein both the input and output drums rotatively reciprocate a predetermined angular amount, and wherein the output clutch drum is intermittently rotated in one direction by the input clutch drum which is rotatively reciprocatively driven without reversing rotation of the output clutch drum. Such spring clutches are widely used in such areas as, for example, dispensing machines wherein a metered amount of beverage is dispensed. It has been heretofore not shown, however, how to provide for control of the width of the cross-over slot or gap which is essential to provide, during the operative life of the spring clutch, accurate angular rotation of the output drum. Reliable output rotation is disrupted by accumulation of contaminants such as dirt and oil upon the surface of the clutch which causes wear in the area of the slot or gap and thereby changes the effective width of the slot or gap. It is therefore essential that a spring clutch of the type as herein described be provided with an adjustment feature directed to convenient control of the width of the cross-over gap so that accurate angular rotation of the output clutch drum is maintainable in spite of wear. Such adjustment feature also increases the versitility of a spring clutch having intermittent angular output in that it can be field-adjusted to produce any desired degree of angular output. It is thus a principal object of the present invention to provide a coil spring clutch wherein output of the output clutch drum is conveniently and expeditiously regulated to provide for a predetermined intermittent constant angular output throughout its entire operative life.
It is another object of this invention to provide a spring clutch wherein the intermittent angular output is capable of being varied by field-adjustment of the spring clutch.